Question

将Feign客户端呈现为：

@FeignClient(name = "storeClient", url = "${feign.url}")
public interface StoreClient {
    //..
}

是否可以利用环境变化的Spring Cloud功能在运行时更改Feign URL？（更改feign.url属性并调用/refresh端点）

Answer 1

作为一种可能的解决方案-可以引入RequestInterceptor以便通过RequestTemplate中定义的属性在RefreshScope中设置URL。

要实施此方法，您应该执行以下操作：

在ConfigurationProperties

中定义Component RefreshScope

@Component
@RefreshScope
@ConfigurationProperties("storeclient")
public class StoreClientProperties {
    private String url;
    ...
}

在application.yml
中指定客户端的默认URL
```
storeclient
    url: https://someurl
```

定义RequestInterceptor，它将切换URL

@Configuration
public class StoreClientConfiguration {

    @Autowired
    private StoreClientProperties storeClientProperties;

    @Bean
    public RequestInterceptor urlInterceptor() {
        return template -> template.insert(0, storeClientProperties.getUrl());
    }

}

在您的FeignClient定义中使用一些占位符作为URL，因为它将不被使用

@FeignClient(name = "storeClient", url = "NOT_USED")
public interface StoreClient {
    //..
}

现在storeclient.url可以刷新，定义的URL将在RequestTemplate中用于发送http请求。

Answer 2

RequestInterceptor的扩展答案：

application.yml

app:
  api-url: http://external.system/messages
  callback-url: http://localhost:8085/callback

@ConfigurationProperties

@Component
@RefreshScope
@ConfigurationProperties("app")
public class AppProperties {
    private String apiUrl;
    private String callbackUrl;
    ...
}

@FeignClient-s配置

请确保您的...ClientConfig类未使用任何@Component / ...注释进行注释，或者未通过组件扫描找到。

public class ApiClientConfig {
    @Bean
    public RequestInterceptor requestInterceptor(AppProperties appProperties) {
        return requestTemplate -> requestTemplate.target(appProperties.getApiUrl());
    }
}

public class CallbackClientConfig {
    @Bean
    public RequestInterceptor requestInterceptor(AppProperties appProperties) {
        return requestTemplate -> requestTemplate.target(appProperties.getCallbackUrl());
    }
}

@FeignClient-s

@FeignClient(name = "apiClient", url = "NOT_USED", configuration = ApiClientConfig.class)
public interface ApiClient {
    ...
}

@FeignClient(name = "callbackClient", url = "NOT_USED", configuration = CallbackClientConfig.class)
public interface CallbackClient {
    ...
}

在运行时更改FeignClient URL

2 个答案: